Optical fibre digital pulse-position-modulation assuming a Gaussian received pulse shape

Spectral characterisation of n k pulse position modulation format

“…Introduction: Conventional n-ary pulse position modulation (PPM) has been proposed for the optical fibre [1], optical wireless [2] and optical satellite [3] channels due to its enhanced sensitivity performance. However, this is at the cost of significant bandwidth expansion and so alternative, more bandwidth efficient schemes, have been proposed such as multiple PPM [4,5] in which k-pulses are positioned within a time frame containing S -slots leading to S k symbols per frame.…”

Performance evaluation of optically preamplified dicode pulse position modulation receivers

“…Early work on DiPPM also includes work on optical wireless communications [2] and spectral characterisation [3]. The operation of PPM has been widely investigated in relation to different receiver configurations and is known to offer significantly higher sensitivity than receivers detecting standard on-off keyed non-return-tozero (OOK NRZ) modulation but at the expense of bandwidth [4][5][6]. This success makes it natural to try and find an alternative modulation format that retains some of the sensitivity benefits of PPM without the excessive bandwidth consumption and it is claimed in Reference [1] that DiPPM does indeed do this-the sensitivity benefit coming with only a fourfold increase in the line rate over the OOK NRZ data rate.…”

“…In PPM M bits of binary data are represented by the position of a pulse within one of the 2 M data bearing slots in the PPM frame [4][5][6]. At the end of each PPM frame there are also some guard slots present to minimise ISI.…”

“…Assuming that a leading edge threshold detection scheme is adopted (as typically proposed for fibre PPM [4][5][6]) there are (similar to PPM) three types of errors in dicode PPM, namely erasure, wrong-slot and false alarm errors. An erasure error occurs when noise destroys the pulse in the time frame to such an extent that it is impossible to be detected by the receiver as it never crosses the threshold level.…”

n k -pulse position modulation for optical wireless communication

“…Introduction: Conventional n-ary pulse position modulation (PPM) has been proposed for optical fibre [1], optical wireless [2] and optical satellite [3] channels, owing to its enhanced sensitivity performance. In this format, L bits (where L is termed the coding level) of pulse code modulation (PCM) are encoded into PPM by positioning a single pulse in one of 2 L time slots.…”